drm/ttm: cleanup and optimize ttm_bo_mem_compat v2

No need to implement the same logic twice. Also check if the busy placements
are identical to the already scanned placements before checking them.

v2: improve check even more as suggested by Michel.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/ttm/ttm_bo.c

@@ -1020,16 +1020,17 @@ static int ttm_bo_move_buffer(struct ttm_buffer_object *bo,
 	return ret;
 }
 
-bool ttm_bo_mem_compat(struct ttm_placement *placement,
+static bool ttm_bo_places_compat(const struct ttm_place *places,
+				 unsigned num_placement,
 				 struct ttm_mem_reg *mem,
 				 uint32_t *new_flags)
 {
-	int i;
+	unsigned i;
 
-	for (i = 0; i < placement->num_placement; i++) {
-		const struct ttm_place *heap = &placement->placement[i];
-		if (mem->mm_node &&
-		    (mem->start < heap->fpfn ||
+	for (i = 0; i < num_placement; i++) {
+		const struct ttm_place *heap = &places[i];
+
+		if (mem->mm_node && (mem->start < heap->fpfn ||
 		     (heap->lpfn != 0 && (mem->start + mem->num_pages) > heap->lpfn)))
 			continue;
 
@@ -1038,19 +1039,23 @@ bool ttm_bo_mem_compat(struct ttm_placement *placement,
 		    (*new_flags & mem->placement & TTM_PL_MASK_MEM))
 			return true;
 	}
+	return false;
+}
 
-	for (i = 0; i < placement->num_busy_placement; i++) {
-		const struct ttm_place *heap = &placement->busy_placement[i];
-		if (mem->mm_node &&
-		    (mem->start < heap->fpfn ||
-		     (heap->lpfn != 0 && (mem->start + mem->num_pages) > heap->lpfn)))
-			continue;
+bool ttm_bo_mem_compat(struct ttm_placement *placement,
+		       struct ttm_mem_reg *mem,
+		       uint32_t *new_flags)
+{
+	if (ttm_bo_places_compat(placement->placement, placement->num_placement,
+				 mem, new_flags))
+		return true;
 
-		*new_flags = heap->flags;
-		if ((*new_flags & mem->placement & TTM_PL_MASK_CACHING) &&
-		    (*new_flags & mem->placement & TTM_PL_MASK_MEM))
+	if ((placement->busy_placement != placement->placement ||
+	     placement->num_busy_placement > placement->num_placement) &&
+	    ttm_bo_places_compat(placement->busy_placement,
+				 placement->num_busy_placement,
+				 mem, new_flags))
 		return true;
-	}
 
 	return false;
 }